ltt/branches/poly/lttv/module.c

   1
   2 /* module.c : Implementation of the module loading/unloading mechanism.
   3  *
   4  */
   5
   6 #include <lttv/module.h>
   7
   8
   9 struct _LttvModule
  10 {
  11   GModule *module;
  12   guint ref_count;
  13   guint load_count;
  14   GPtrArray *dependents;
  15 };
  16
  17
  18 /* Table of loaded modules and paths where to search for modules */
  19
  20 static GHashTable *modules = NULL;
  21
  22 static GPtrArray *modulesPaths = NULL;
  23
  24 static void lttv_module_unload_all();
  25
  26
  27 void lttv_module_init(int argc, char **argv)
  28 {
  29   modules = g_hash_table_new(g_str_hash, g_str_equal);
  30   modulesPaths = g_ptr_array_new();
  31 }
  32
  33
  34 void lttv_module_destroy()
  35 {
  36   int i;
  37
  38   /* Unload all modules */
  39   lttv_module_unload_all();
  40
  41   /* Free the modules paths pointer array as well as the elements */
  42   for(i = 0; i < modulesPaths->len ; i++) {
  43     g_free(modulesPaths->pdata[i]);
  44   }
  45   g_ptr_array_free(modulesPaths,TRUE) ;
  46   modulesPaths = NULL;
  47
  48   /* destroy the hash table */
  49   g_hash_table_destroy(modules) ;
  50   modules = NULL;
  51 }
  52
  53
  54 /* Add a new pathname to the modules loading search path */
  55
  56 void lttv_module_path_add(const char *name)
  57 {
  58   g_ptr_array_add(modulesPaths,(char*)g_strdup(name));
  59 }
  60
  61
  62 static LttvModuleInfo *
  63 module_load(const char *name, int argc, char **argv)
  64 {
  65   GModule *gm;
  66
  67   LttvModule *m;
  68
  69   int i;
  70
  71   char *pathname;
  72
  73   LttvModuleInit init_function;
  74
  75   /* Try to find the module along all the user specified paths */
  76
  77   for(i = 0 ; i < modulesPaths->len ; i++) {
  78     pathname = g_module_build_path(modulesPaths->pdata[i],name);
  79     gm = g_module_open(pathname,0);
  80     g_free(pathname);
  81
  82     if(gm != NULL) break;
  83   }
  84
  85   /* Try the default system path */
  86
  87   if(gm == NULL) {
  88     pathname = g_module_build_path(NULL,name);
  89     gm = g_module_open(pathname,0);
  90     g_free(pathname);
  91   }
  92
  93   /* Module cannot be found */
  94
  95   if(gm == NULL) return NULL;
  96
  97   /* Check if the module was already opened using the hopefully canonical name
  98      returned by g_module_name. */
  99
 100   pathname = g_module_name(gm);
 101
 102   m = g_hash_table_lookup(modules, pathname);
 103
 104   if(m == NULL) {
 105
 106     /* Module loaded for the first time. Insert it in the table and call the
 107        init function if any. */
 108
 109     m = g_new(LttvModule);
 110     m->module = gm;
 111     m->ref_count = 0;
 112     m->load_count = 0;
 113     m->dependents = g_ptr_array_new();
 114     g_hash_table_insert(modules, pathname, m);
 115
 116     if(!g_module_symbol(gm, "init", (gpointer)&init_function)) {
 117       g_warning("module %s (%s) has no init function", name, pathname);
 118     }
 119     else init_Function(argc,argv);
 120   }
 121   else {
 122
 123     /* Module was already opened, check that it really is the same and
 124        undo the extra g_module_open */
 125
 126     if(m->module != gm) g_error("Two gmodules with the same pathname");
 127     g_module_close(gm);
 128   }
 129
 130   m->ref_count++;
 131   return m;
 132 }
 133
 134
 135 LttvModuleInfo *
 136 lttv_module_load(const char *name, int argc, char **argv)
 137 {
 138   LttvModule *m = module_load(name, argc, argv);
 139
 140   if(m != NULL) m->load_count++;
 141   return m;
 142 }
 143
 144
 145 LttvModule *
 146 lttv_module_require(LttvModule *m, const char *name, int argc, char **argv)
 147 {
 148   LttvModule *module;
 149
 150   module = module_load(name, argc, argv);
 151   if(module != NULL) g_ptr_array_add(m->dependents, module);
 152   return module;
 153 }
 154
 155
 156 static void module_unload(LttvModule *m)
 157 {
 158   LttvModuleDestroy destroy_function;
 159
 160   char *pathname;
 161
 162   guint len;
 163
 164   /* Decrement the reference count */
 165
 166   m->ref_count--;
 167   if(m->ref_count > 0) return;
 168
 169   /* We really have to unload the module, first unload its dependents */
 170
 171   len = m->dependents->len;
 172
 173   for(i = 0 ; i < len ; i++) {
 174     module_unload(m->dependents->pdata[i]);
 175   }
 176
 177   if(len != m->dependents->len) g_error("dependents list modified");
 178
 179   /* Unload the module itself */
 180
 181   if(!g_module_symbol(m->module, "destroy", (gpointer)&destroy_function)) {
 182     g_warning("module (%s) has no destroy function", pathname);
 183   }
 184   else destroy_function();
 185
 186   g_hash_table_remove(modules, g_module_name(m->module));
 187   g_ptr_array_free(m->dependents, TRUE);
 188   g_module_close(m->module);
 189   g_free(m);
 190 }
 191
 192
 193 void lttv_module_unload(LttvModule *m)
 194 {
 195   if(m->load_count <= 0) {
 196     g_error("more unload than load (%s)", g_module_name(m->module));
 197     return;
 198   }
 199   m->load_count--;
 200   module_unload(m);
 201 }
 202
 203
 204 static void
 205 list_modules(gpointer key, gpointer value, gpointer user_data)
 206 {
 207   g_ptr_array_add((GPtrArray *)user_data, value);
 208 }
 209
 210
 211 LttvModule **
 212 lttv_module_list(guint *nb)
 213 {
 214   GPtrArray *list = g_ptr_array_new();
 215
 216   LttvModule **array;
 217
 218   g_hash_table_foreach(modules, list_modules, list);
 219   *nb = list->len;
 220   array = (LttvModule **)list->pdata;
 221   g_ptr_array_free(list, FALSE);
 222   return array;
 223 }
 224
 225
 226 LttvModule **
 227 lttv_module_info(LttvModule *m, const char **name,
 228     guint *ref_count, guint *load_count, guint *nb_dependents)
 229 {
 230   guint i, len = m->dependents->len;
 231
 232   LttvModule **array = g_new(LttvModule *, len);
 233
 234   *name = g_module_name(m->module);
 235   *ref_count = m->ref_count;
 236   *load_count = m->load_count;
 237   *nb_dependents = len;
 238   for(i = 0 ; i < len ; i++) array[i] = m->dependents->pdata[i];
 239   return array;
 240 }
 241
 242
 243 static void
 244 list_independent(gpointer key, gpointer value, gpointer user_data)
 245 {
 246   LttvModule *m = (LttvModule *)value;
 247
 248   if(m->load_count > 0) g_ptr_array_add((GPtrArray *)user_data, m);
 249 }
 250
 251
 252 void
 253 lttv_module_unload_all()
 254 {
 255   guint i;
 256
 257   LttvModule *m;
 258
 259   GPtrArray *independent_modules = g_ptr_array_new();
 260
 261   g_hash_table_foreach(modules, list_independent, independent_modules);
 262
 263   for(i = 0 ; i < independent_modules->len ; i++) {
 264     m = (LttvModule)independent_modules->pdata[i];
 265     while(m->load_count > 0) lttv_module_unload(m);
 266   }
 267
 268   g_ptr_array_free(independent_modules, TRUE);
 269   if(g_hash_table_size(modules) != 0) g_warning("cannot unload all modules");
 270 }